Military fighter and attack aircraft typically provide ingress to and egress from the cockpit via a movable canopy which encloses the upper portion of the cockpit. The canopy is either slidable or pivotable into an open position to establish an opening through which a crew member can enter into or exit from the cockpit. Furthermore, access to the cockpit by ground crew for maintenance and other support services is also through the open canopy.
Although the movable-canopy system for accessing a cockpit has been the standard system for many years, there are several distinct disadvantages of such systems. First, the aircraft cockpit on many fighter aircraft is at a substantial height above the ground. Accordingly, a crew member generally must climb a ladder to gain access to the cockpit and to reach the ground safely upon exiting the cockpit. When a ladder is not readily available, the crew member conceivably can jump to the ground when a hasty exit is required, but the crew member may easily be injured doing so. Thus, the accessibility to the cockpit provided by movable-canopy systems is inconvenient, and potentially dangerous.
A second disadvantage of movable-canopy access systems is that cockpit instrument displays must be designed to allow a crew member to get into a crew seat from above and, accordingly, constraints are put on the permissble locations and sizes of the displays.
Yet another disadvantage of movable-canopy systems is that when the aircraft is on the ground and the canopy is open, the crew member is exposed to chemical, biological, or radiation fallout.